Wafer scrubbing brush core

ABSTRACT

A brush core and the method for making a brush core for use in substrate scrubbing are provided. The substrate can be any substrate that may need to undergo a scrubbing operation to complete a cleaning operation, etching operation, or other preparation. For instance, the substrate can be a semiconductor wafer, a disk, or any other type of work piece that will benefit from a brush core that can deliver uniform controlled amounts of fluid through the brush along an entire length of the brush core. The brush core is defined by a tubular core having a length that extends between a first end and a second end. The first end has an opening into a bore that is defined through a middle of the tubular core and extends along an inner length of the tubular core. A first plurality of holes are oriented along a plurality of first lines that extend in the direction of the length of the tubular core, and each of the first plurality of holes define paths to the bore of the tubular core. A second plurality of holes are oriented along a plurality of second lines that extend in the direction of the length of the tubular core, and each of the second plurality of holes define paths to the core of the tubular core. The plurality of first lines and the plurality of second lines alternate and the holes of the first and second plurality of holes are equally spaced apart. The holes of the second plurality of holes are offset relative to the holes of the first plurality of holes.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to semiconductor wafer fabrication, andmore particularly to semiconductor wafer scrubbing equipment.

2. Description of the Related Art

As is well known, semiconductor devices are fabricated fromsemiconductor wafers, which are subjected to numerous processingoperations. These operations include, for example, impurity implants,gate oxide generation, inter-metal oxide depositions, metallizationdepositions, photolithography pattering, etching operations, chemicalmechanical polishing (CMP), etc. Although these processes are performedin ultra clean environments, the very nature of many of the processoperations is to blame for the generation of surface particles andresidues. For instance, when CMP operations are performed, a film ofparticles and/or metal contaminants are commonly left behind.

Because surface particles can detrimentally impact the performance of anintegrated circuit device, wafer cleaning operations have become astandard procedural requirement after certain process steps. Althoughcleaning operations are rather procedural, the equipment and chemicalsimplemented to perform the actual cleaning are highly specialized. Thisspecialization is important because each wafer, being at differentstages of fabrication, represents a significant investment in terms ofraw materials, equipment fabrication time, and associated research anddevelopment.

To perform the cleaning operations in an automated manner, fabricationlabs employ cleaning systems. The cleaning systems typically include oneor more brush boxes in which wafers are scrubbed. Each brush boxincludes a pair of brushes, such that each brush scrubs a respectiveside of a wafer. To enhance the cleaning ability of such brush boxes, itis common practice to deliver cleaning fluids through the brush (TTB).TTB fluid delivery is accomplished by implementing brush cores that havea plurality of holes that allow fluids being fed into the brush core ata particular pressure to be released into an outer brush surface. Theouter brush surface is made out of a very porous and soft material sothat direct contact with the delicate surface of a wafer does not causescratches or other damage. Typically, the outer brush surface is a madeout of polyvinyl alcohol (PVA) foam. Although, other materials such asnylon, mohair or a mandrel wrapped with a polishing pad material can beused.

As semiconductor design and performance requirements continue increase,cleaning engineers are also challenged to improve their associatedprocesses. To meet these demands, the same cleaning equipment is nowbeing used to perform operations other than basic de-ionized (DI) watercleaning. Such operations include the application of sophisticatedchemicals TTB to remove particulates and/or to etch precision amounts ofmaterials from the surfaces of a wafer. Although much research anddevelopment goes into the design of cleaning and etching chemicals, theeffectiveness of such chemicals is only as good as their delivery andapplication onto the surface of a wafer.

Recent research of conventional brush core technology has uncoverednon-uniformities in the application of the chemicals onto the surface ofwafers. The research indicates that although chemicals are being flushedout of the brush cores and onto the wafer surfaces, the appliedchemicals do exit the holes of the brush core at the same rate over thelength of a core. For instance, chemicals are generally supplied to aninternal bore of a brush core from one end of the brush core at a givenpressure. Ideally, the chemicals are expected to flow through the boreand drip or flow out of the core equally from all of the brush coreholes (e.g., the same amount drips out each of holes all along the brushcore). Unfortunately, research shows that chemicals are not dripping outof all of the holes at the same or substantially the same rate. In fact,much of the research indicates that the brush core holes near thechemical receiving end drip out chemicals at a substantially faster ratethan holes at the opposite side of the chemical receiving end.

Because traditional cleaning typically only included the application ofDI water and/or ammonia based chemicals, the uneven application of thesefluids through the brush core did not in many cases detrimentally impactcleaning performance. However, because most cleaning systems are nowrequired to also apply engineered chemicals, such as hydrofluoric acid(HF) containing etch chemicals, any uneven application will have asevere impact on the wafer being processed. For instance, if more HF isapplied to one part of the wafer and less is applied to another part ofthe wafer, the surface of the processed wafer may exhibit performanceimpacting etch variations due to experienced chemical concentrationvariations.

FIG. 1A provides a simplified diagram 10 of a prior art brush core 12having a plurality of holes 12 a. The brush core 12 has a center bore 12b which is configured to receive fluids from a fluid input 16 at one endof the brush core 12. The brush core 12 is shown having a brush 14mounted thereon to illustrate that fluid that enters the bore 12 b exitsthe holes 12 a soaks the brush 14 that is designed to contact a wafer.This simplistic diagram also illustrates fluid flow lines 18 a and 18 b,in which fluid lines 18 a illustrate that more fluid tends to flow outof holes 12 a near the fluid input than at the opposite end. It isbelieved that this occurs because chemicals are either not applied tothe brush core 12 at a sufficient pressure or the holes 12 are too largeand/or are improperly arranged and thus allow gravity to pull more fluidout of the brush core 12 near the fluid input 16 than at the oppositeend.

Some of these prior art brush cores 12 have a center bore 12 b that isabout 0.36 inch in diameter or larger and holes 12 a that are about 0.13inch in diameter or larger. To compensate for the larger size of thesedimensions and to attempt to prevent the uneven delivery of fluids,cleaning systems need to deliver fluids to the brush cores 12 at higherpressures. These higher pressures range between 30 to 35 PSI or higher.However, the application of higher pressures require the cleaning systemto have access to facilities and associated equipment that can deliverthe desired controlled pressures at all times. However, cleaning systemsare installed in clean rooms around the world having differentfacilities which may or may not be able to deliver the recommendedpressures. Additionally, the holes 12 a of most prior art brush cores 12are arranged such that one hole 12 a′ is directly opposite of anotherhole 12 a′. This arrangement is also believed to contribute to thehigher outflow of fluids near the fluid input 16 than at the oppositeend.

In view of the foregoing, there is a need for improved brush coredesigns that enable controlled amounts of fluid to be evenly deliveredand distributed over the surface areas of a brush core.

SUMMARY OF THE INVENTION

Broadly speaking, the present invention fills these needs by providing abrush core for use in scrubbing substrates. The substrate can be anysubstrate that may need to undergo a scrubbing operation to complete acleaning operation, etching operation, or other preparation. Forinstance, the substrate can be a semiconductor wafer, a disk, or anyother type of work piece that will benefit from a brush core that candeliver uniform controlled amounts of fluid through the brush along anentire length of the brush core. It should be appreciated that thepresent invention can be implemented in numerous ways, including as aprocess, an apparatus, a system, a device, or a method. Severalinventive embodiments of the present invention are described below.

In one embodiment, a brush core for use in substrate scrubbing isdisclosed. The brush core is defined by a tubular core extending betweena first end and a second end. A bore is defined through a middle of thetubular core. A first and second plurality of holes are provided. Eachhole of the first and second plurality of holes is defined through thetubular core to define a path to the bore. The first plurality of holesis defined along a first line that extends between the first end and thesecond end and the second plurality of holes is defined along a secondline that extends between the first end and the second end. The firstline and the second line are repeated around the tubular core and thefirst line and the second line alternate around the tubular core, andthe holes of the first plurality of holes are offset relative to theholes of the second plurality of holes.

In another embodiment, a brush core is disclosed. The brush core isdefined by a tubular core having a length that extends between a firstend and a second end. The first end has an opening into a bore that isdefined through a middle of the tubular core and extends along an innerlength of the tubular core. A first plurality of holes are orientedalong a plurality of first lines that extend in the direction of thelength of the tubular core, and each of the first plurality of holesdefine paths to the bore of the tubular core. A second plurality ofholes are oriented along a plurality of second lines that extend in thedirection of the length of the tubular core, and each of the secondplurality of holes define paths to the core of the tubular core. Theplurality of first lines and the plurality of second lines alternate andthe holes of the first and second plurality of holes are equally spacedapart. The holes of the second plurality of holes are offset relative tothe holes of the first plurality of holes.

In yet a further embodiment, a method of making a brush core isdisclosed. The method includes providing a tubular core having a lengththat is configured to extend over a substrate. A bore is defined througha center of the tubular core. A first plurality of holes oriented alonga plurality of first lines that extend in the direction of the length ofthe tubular core is defined. Each of the first plurality of holes isconfigured to establish paths to the bore of the tubular core. A secondplurality of holes oriented along a plurality of second lines thatextend in the direction of the length of the tubular core is defined.Each of the second plurality of holes is configured to establish pathsto the core of the tubular core. The defined first plurality of holesare configured to be offset from the defined second plurality of holes.

Advantageously, the embodiments of the present invention provide brushcores for delivering a uniform fluid distribution throughout the core.The uniform fluid distribution is achieved by designing specially placedand sized holes into the brush core. The holes define paths to aspecially designed center bore, which is configured and sized to quicklypressurize the bore such that the delivered fluid exits the plurality ofholes at about the same rate. Achieving this substantial even outflow offluid from the core along the entire length of the brush core ensuresthat the outer brush receives equal amounts of fluids during anapplication process. As can be appreciated, even outflow of fluids isespecially important when the fluids are engineered chemicals, such asetchants, that are designed to remove certain material particles, films,or layers.

Other aspects and advantages of the invention will become apparent fromthe following detailed description, taken in conjunction with theaccompanying drawings, illustrating by way of example the principles ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be readily understood by the followingdetailed description in conjunction with the accompanying drawings, andlike reference numerals designate like structural elements.

FIG. 1A provides a simplified diagram of a prior art brush core having aplurality of holes.

FIG. 1B shows a wafer cleaning station of the present invention that maybe controlled in an automated way by a cleaning control station.

FIG. 1C shows a more detailed schematic of an exemplary wafer cleaningstation, in accordance with one embodiment of the present invention.

FIG. 2A illustrates a simplified three-dimensional diagram of a pair ofbrushes scrubbing a top surface and a bottom surface of a wafer, inaccordance with one embodiment of the present invention.

FIGS. 2B and 2C illustrate cross-sectional views of two differentorientations for scrubbing a wafer, in accordance with one embodiment ofthe present invention.

FIG. 3 illustrates a three-dimensional view of a brush core, inaccordance with one embodiment of the present invention.

FIGS. 4A through 4C illustrate alternative channel geometries for atubular core, in accordance with one embodiment of the presentinvention.

FIG. 5A shows a cross-sectional view of the brush core, in accordancewith one embodiment of the present invention.

FIGS. 5B and 5C illustrate cross-sectional views A—A and B—B along abrush core, in accordance with one embodiment of the present invention.

FIG. 6 illustrates a simplified diagram of a plurality of channelshaving a plurality of holes, in accordance with one embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An invention is described for a brush core for use in scrubbingsubstrates. The substrate can be any substrate that may need to undergoa scrubbing operation to complete a cleaning operation, etchingoperation, or other preparation. It will be obvious, however, to oneskilled in the art, that the present invention may be practiced withoutsome or all of these specific details. In other instances, well knownprocess operations have not been described in detail in order not tounnecessarily obscure the present invention.

FIG. 1B shows a wafer cleaning station 100 of the present invention thatmay be controlled in an automated way by a cleaning control station 102.The wafer cleaning station 100 includes a sender station 104, a cleaningstage 106, a spin-rinse and dry (SRD) station 108, and a receiverstation 110. As a broad overview of the cleaning process, semiconductorwafers are initially placed into the sender station 104. The senderstation 104 then delivers a wafer (one-at-a-time) to the cleaning stage106. In one embodiment, the cleaning stage 106 is divided into a firstcleaning stage 106 a and a second cleaning stage 106 b, although havingjust one cleaning stage 106 will also work. After passing through thecleaning stage 106, the wafer is passed through an exit spray in orderto remove the cleaning fluids and any contaminants. The SRD station 108dries the wafer and then it is delivered to the receiver station 110 fortemporary storage.

FIG. 1C shows a more detailed schematic of an exemplary wafer cleaningstation 100. Both the sender station 104 and the receiving station 110are preferably adapted to receive a cassette containing a number ofwafers. The first and second cleaning stages 106 a and 106 b preferablyinclude a set of PVA brushes 120 that are very soft and porous. As willbe described below, the brushes 120 are mounted on brush cores 200 ofthe present invention. As is well known, the brushes 120 are capable ofscrubbing the wafer clean without damaging the delicate surface.

FIG. 2A illustrates a simplified three-dimensional diagram of a pair ofbrushes 120 a and 120 b for scrubbing a top surface and a bottomsurface, respectively, of a wafer 130. Typically, the wafer 130 iscaused to rotate in a particular direction while the brushes 120 rotatearound an axis of rotation while the surface of the brushes 120 are incontact with the surfaces of the wafer 130. The brushes 120 a and 120 bare mounted on brush cores 200 a and 200 b. The brush cores 200 areconfigured to have at one end, a fluid inlet 201 which connects totubing 202. The tubing 202 will thus supply the desired fluids to a bore270 within the brush core 200. The brush core 200, as will be describedin greater detail below, will have a plurality of holes 260 that willallow the fluids provided into the bore 270 to uniformly exit the brushcore 200 (i.e., therefore evenly supplying the desired fluid to thebrushes 120).

FIGS. 2B and 2C illustrate cross-sectional views of two differentorientations for scrubbing a wafer 130, in accordance with oneembodiment of the present invention. As shown in FIG. 2B, the wafer isheld horizontally while a top brush 120 a scrubs the top surface of thewafer 130, and a bottom brush 120 b scrubs the bottom surface of thewafer 130. As mentioned above, the wafer 130 is configured to rotate(using rollers not shown) at the same time that the brushes 120 rotateto ensure that the entire surface area of the wafer is properly scrubbedto remove contaminants or etch the surface to a desired degree. Thus,FIG. 2B illustrates a horizontal wafer scrubber 100 b.

In contrast, FIG. 2C illustrates a vertical wafer scrubber 100 c inwhich the wafer 130 is scrubbed while in a vertical position. Typically,the wafer 130 sits on a pair of rollers of the scrubber 100 c. Thebrushes 120 are configured to rotate in a desired direction such thatboth sides of the wafer 130 are evenly scrubbed, using an equal andopposite pressure on each side of the wafer 130. For more information onvertical wafer scrubbing, reference may be made to U.S. Pat. No.5,875,507, having inventors Stephens et al., entitled “Wafer CleaningApparatus,” which is hereby incorporated reference.

FIG. 3 illustrates a three-dimensional view of a brush core 200, inaccordance with one embodiment of the present invention. The brush core200 is defined by a tubular core 250 that extends between a first end253 and a second end 251. The tubular core is configured to include, inone embodiment, a plurality of channels 252 which are recessed into thesurface of the tubular core 250. One feature of the present invention isto ensure that an even distribution of fluid is provided throughout thebrush core 200. For instance, a fluid source 263 supplies fluid by wayof tubing (not shown) into the bore 270 of the tubular core 250 suchthat the fluid is evenly distributed to each of the plurality of holes260. In a preferred orientation, the plurality of holes 260 of onechannel 252 are arranged in an offset configuration relative to holesdefined in an adjacent respective channel 252.

For instance, one channel may include a first plurality of holes 260aligned along a first line across the length of the tubular core 250,and the next channel that is adjacent to the first channel will have itsplurality of holes 260 defined along a second line across the length ofthe tubular core 250. However, the holes 260 defined in the adjacentchannel 252 will be offset relative to the holes of its respectiveadjacent channel 252. In a preferred embodiment, the holes 260 will beevenly spaced apart and defined along the channel 252 that traverses thelength of the tubular core 250. As shown, the holes 260 of the adjacentchannel are shifted by an amount that is equal to about half of theseparation distance between the holes of the first channel. In oneembodiment, the offset can be any amount so long as some offset isprovided. In this manner, any fluid provided by the fluid source 263into the bore that is defined through the tubular core 250 will evenlydistribute into the bore and emanate out from all of the plurality ofholes defined through the tubular core 250.

In this example, the first end 253 of the brush core 200 includes athreaded insert 262 and an extension 264. This threaded insert 262 andextension 264 are configured to provide a way to connect up to anappropriate fluid line which will deliver fluids (e.g., chemicals, DIwater, or mixtures of fluids) to the bore 270 of the tubular core 250.The second end 251 of the brush core 200 includes a connection hole 256for holding the second end of the brush core 200 in place when it isinstalled into a suitable brush box mechanism. Also shown are aplurality of locking pin holes 254 for engaging the tubular core 250 andenabling the application of a torque rotation to the brush core when thebrush box requires the brush core to rotate about a defined axis.

FIGS. 4A through 4C illustrate alternative channel geometries for thetubular core 250, in accordance with one embodiment of the presentinvention. As shown in FIG. 4A, a radial channel 252 can be defined intothe tubular core 250 so that when the brush 120 is mounted on the brushcore 200, any fluid provided through the plurality of holes 260 can bedistributed along the channel and the length of the tubular core 250.FIG. 4B illustrates an alternative embodiment of the channel 252 a inwhich a slotted channel is provided to achieve the distribution of thefluids along the length of the tubular core 250. In certain embodiments,it may be desired to eliminate the channel altogether as shown in FIG.4C, and rely upon the very porous nature of the PVA brush which willabsorb and evenly distribute the fluids throughout the brush. It shouldbe understood that the actual shape or geometry of the channel can bevaried or eliminated altogether if desired, for the particularapplication.

FIG. 5A shows a cross-sectional view of the brush core 200, inaccordance with one embodiment of the present invention. As shown inthis example, the brush core 200 will include a bore 270 which isdefined along an inner length of the tubular core 250. The plurality ofholes 260 illustrated along the top of the cross section are shown to beoffset relative to the plurality of holes 260 defined along the bottomof the cross-sectional view. This offset design is configured to allowthe even distribution of a fluid flow through the entire length of thebore 270, and thus allow an equal outflow of the fluid flow through eachof the plurality of holes 260. That is, the present design is configuredto allow a fluid flow having a reduced pressure to rapidly fill the bore270 and reach equilibrium such that an equal flow of fluid will emanatefrom the plurality of holes 260 around the entire brush core 200. Thus,holes such as 260 a defined near the first end 253 of the brush core 200will exhibit about the same outflow of fluids as holes such as 260 bdefined at the second end 251 of the brush core 200.

FIGS. 5B and 5C illustrate cross-sectional views 5B—5B and 5C—5C alongthe brush core 200, in accordance with one embodiment of the presentinvention. In this example, FIG. 5B illustrates the cross-sectional viewof cross section 5B—5B, and shows how the holes 260 are arranged aroundthe tubular core 250. In this example, holes are defined around thetubular core 250 at 12 o'clock, 2 o'clock, 4 o'clock, 6 o'clock, 8o'clock, and 10 o'clock. However, at cross section 5B—5B, only holes 260at 12 o'clock, 4 o'clock, and 8 o'clock, are exposed to the fluid flowthat travels down the bore 270.

Because of the offset nature of the plurality of holes 260 that aredefined along lines of the tubular core 250, a cross-sectional view at5C—5C shown in FIG. 5C, illustrates that the holes at 2 o'clock, 6o'clock, and 10 o'clock are now exposed to the fluid flow. In apreferred embodiment, the bore 270 will have a diameter ranging betweenabout 0.060 inch and about 0.35 inch, and more preferably, between about0.125 inch and about 0.30 inch, and most preferably at about 0.25 inch.It should be noted that the diameter of the bore 270 is substantiallysmaller than that typically used or suggested for brush cores of theprior art. By reducing the diameter of the bore 270 to such a reduceddiameter, it has been tested that the fluid flow that enters the bore270 will rapidly fill the volume of the bore 270 within the brush core250.

Because the volume within the bore 270 is rapidly filled, the bore 270will be pressurized rapidly and the fluid will be ready to quicklyoutflow through the plurality of holes 260 all the way around thesurface of the tubular core 250. In this preferred embodiment, each ofthe plurality of holes 260 should have a diameter ranging between about0.005 inch and about 0.092 inch, and most preferably, about 0.050 inch.It should be noted that the diameter of each of the plurality of holes260 is also substantially reduced, which is configured in conjunctionwith the reduced bore 270 diameter to distribute any fluid flowdelivered to the brush core 200 in a more even and distributed mannerthroughout the entire length of the brush core 200. As discussed above,this is a substantial improvement in the art considering that the TTBfluid delivery is now being used to deliver sophisticated chemicals thatare designed to alter the surface materials on a given substrate. Forexample, when chemistries including HF are applied to semiconductorwafer surfaces in an effort to etch certain material layers or films, anuneven application of such chemicals can cause surface damaging surfacevariations.

Continuing with the preferred design characteristics of a brush core200, when the brush core 200 is designed for a 300 mm wafer scrubbingapplication, the brush core may have six channels 252 around the tubularcore 250. Of course, more or less channels may be used (e.g., rangingbetween 2 and 12 channels). The total length L_(A) of the exemplarybrush core 200 is about 14 inches, and the brush 120 will thus have alength L_(B) of about 13 inches. In this embodiment, the length L_(C) ofthe channel 252 will be about 11 inches. Again, it should be understoodthat the length of the brush core 200 can vary and the number of holeswithin the channels 252 can also vary.

FIG. 6 illustrates a simplified diagram of a plurality of channels 252having a plurality of holes 260, in accordance with one embodiment ofthe present invention. In the case where six channels are provided, achannel will be provided at 12 o'clock, 2 o'clock, 4 o'clock, 6 o'clock,8 o'clock, and 10 o'clock. As shown, the orientation of the plurality ofholes 260 along the channels for 12 o'clock, 4 o'clock, and 8 o'clockbegin at the same location of their respective channel 252. Each of theplurality of holes 260 are separated by a separation distance S. In oneembodiment, the separation distance is about 1.26 inch.

The separation distance S is selected such that an even spacing can bedistributed along the distance of a selected channel. Thus, if thechannel is longer or shorter, the separation S will be modified to meetthe desired length of a given channel. In the exemplary embodiment ofthe present invention, the channel length is about 11 inches, andtherefore the separation between each of the plurality of holes 260 isas described above about 1.26 inch. The holes in the adjacent channels252 defined at 2 o'clock, 6 o'clock, and 10 o'clock, are offset relativeto the holes of the first plurality of channels defined at 12 o'clock, 4o'clock, and 8 o'clock.

This offset is preferably about half the distance of the separationparameter S. As pictorially illustrated, the offset between the channelof 12 o'clock and 2 o'clock is defined by an offset separation (OS) ofabout 0.63 inch. It should be understood that these parameters are onlyexemplary in nature and may be modified so long as some offsetorientation is maintained to ensure even distribution of a fluid thatmay be provided into the bore 270.

It is again noted that the brush core of the present invention can bemodified for use in scrubbing any number of substrate types, forexample, semiconductor wafers, hard drive discs, flat panel displays,and the like. Additionally, the brush core can be modified for substratescrubbing applications of any size, for example, 100 mm wafers, 200 mmwafers, 300 mm wafers, larger wafers, small hard disks, etc. It shouldalso be noted that any number of fluids can be delivered through thebrush (TTB), for example, DI water, ammonia containing chemicalmixtures, HF containing chemical mixtures, surfactant containingchemical mixtures, and many other variations.

For more information on wafer scrubbing brush technology, reference canbe made to U.S. Pat. No. 5,806,126, having inventors de Larios et al.,entitled “Apparatus For A Brush Assembly,” and U.S. patent applicationNo. 09/112,666, having inventors Vail et al., entitled “Brush InterflowDistributor.” This U.S. Patent and U.S. Patent Application are herebyincorporated by reference.

For additional information on wafer preparing systems and techniques,reference may be made to commonly owned U.S. patent application Nos. (1)08/792,093, filed Jan. 31, 1997now U.S. Pat. No. 5,858,109, entitled“Method And Apparatus For Cleaning Of Semiconductor Substrates UsingStandard Clean 1 (SC1),” (2) 08/542,531, filed Oct. 13, 1995 now U.S.Pat. No. 5,806,128, entitled “Method and Apparatus for Chemical DeliveryThrough the Brush,” and (3) 09/277,712, filed Mar. 26, 1999, entitled“Pressure Fluctuation Dampening System.” All three U.S. patentapplications are hereby incorporated by reference.

Although the foregoing invention has been described in some detail forpurposes of clarity of understanding, it will be apparent that certainchanges and modifications may be practiced within the scope of theappended claims. Accordingly, the present embodiments are to beconsidered as illustrative and not restrictive, and the invention is notto be limited to the details given herein, but may be modified withinthe scope and equivalents of the appended claims.

What is claimed is:
 1. A brush core for use in substrate scrubbing,comprising: a tubular core extending between a first end and a secondend; a bore defined through a middle of the tubular core; a firstplurality of holes, each hole of the first plurality of holes beingdefined through the tubular core to define a path to the bore, the firstplurality of holes being defined along a first line that extends betweenthe first end and the second end; and a second plurality of holes, eachhole of the second plurality of holes being defined through the tubularcore to define the path to the bore, the second plurality of holes beingdefined along a second line that extends between the first end and thesecond end, the first line and the second line are repeated around thetubular core and the first line and the second line alternate around thetubular core, and wherein the holes of the first plurality of holes areoffset relative to the holes of the second plurality of holes, and eachof the first lines and the second lines are defined along channels thatare defined into an outer surface of the tubular core.
 2. A brush corefor use in substrate scrubbing as recited in claim 1, wherein a firsthole of the first plurality of holes is defined at a start of thechannel defined along the first line that extends between the first endand the second end, and a first hole of the second plurality of holes isdefined at an offset from the start of the channel defined along thesecond line that extends between the first end and the second end.
 3. Abrush core for use in substrate scrubbing as recited in claim 2, whereinthe first hole of the first plurality of holes is offset from the firsthole of the second plurality of holes by about 0.36 inch, and each holeof the first and second plurality of holes is separated by about 1.26inch.
 4. A brush core for use in substrate scrubbing as recited in claim3, further comprising: a brush being configured to fit over the brushcore.
 5. A brush core for use in substrate scrubbing as recited in claim1, wherein each of the first and second plurality of holes has adiameter ranging between about 0.005 inch and about 0.092 inch.
 6. Abrush core for use in substrate scrubbing as recited in claim 5, whereinthe bore has a diameter ranging between about 0.060 inch and about 0.35inch.
 7. A brush core for use in substrate scrubbing as recited in claim1, wherein the brush core is configured for a substrate in the range of100 mm to 300 mm.
 8. A brush core for use in substrate scrubbing asrecited in claim 1, wherein the first plurality of holes are definedalong three channels and the second plurality of holes are defined alongthree channels.
 9. A brush core for use in substrate scrubbing asrecited in claim 1, wherein the 2 to 12 channels are defined around thetubular core.
 10. A brush core for use in substrate scrubbing as recitedin claim 1, wherein a pressure ranging between about 1 PSI and 35 PSI isapplied to the bore in order to distribute a fluid out of the first andsecond plurality of holes that extend between the first end and thesecond end.
 11. A brush core, comprising: a tubular core having a lengththat extends between a first end and a second end, the first end havingan opening into a bore that is defined through a middle of the tubularcore and extends along an inner length of the tubular core; a firstplurality of holes oriented along a plurality of first lines that extendin the direction of the length of the tubular core, each of the firstplurality of holes defining paths to the bore of the tubular core; asecond plurality of holes oriented along a plurality of second linesthat extend in the direction of the length of the tubular core, each ofthe second plurality of holes defining paths to the core of the tubularcore; the plurality of first lines and the plurality of second linesalternate, the holes of the first and second plurality of holes areequally spaced apart, and the holes of the second plurality of holes areoffset relative to the holes of the first plurality of holes; and aplurality of channels defined along the first and second plurality oflines, the plurality of channels defining recesses for distributing afluid emanating from the bore and exiting the first and second pluralityof holes.
 12. A brush core as recited in claim 11, wherein each of thefirst and second plurality of holes has a diameter ranging between about0.005 inch and about 0.092 inch.
 13. A brush core, comprising: a tubularcore having a length that extends between a first end and a second end,the first end having an opening into a bore that is defined through amiddle of the tubular core and extends along an inner length of thetubular core; a first plurality of holes oriented along a plurality offirst lines that extend in the direction of the length of the tubularcore, each of the first plurality of holes defining paths to the bore ofthe tubular core; a second plurality of holes oriented along a pluralityof second lines that extend in the direction of the length of thetubular core, each of the second plurality of holes defining paths tothe core of the tubular core; the plurality of first lines and theplurality of second lines alternate, the holes of the first and secondplurality of holes are equally spaced apart, and the holes of the secondplurality of holes are offset relative to the holes of the firstplurality of holes; and wherein the bore has a diameter ranging betweenabout 0.060 inch and about 0.35 inch.
 14. A brush core as recited inclaim 13, wherein the brush core is configured for a substrate in therange of 100 mm to 300 mm.
 15. A brush core as recited in claim 13,wherein a spacing that defines the equally spaced apart orientation ofthe first and second plurality of holes is about 1.26 inch for a 300 mmbrush core, and the offset is about 0.36 inch.
 16. A method of making abrush core, comprising: providing a tubular core having a length that isconfigured to extend over a substrate; defining a bore through a centerof the tubular core; defining a first plurality of holes oriented alonga plurality of first lines that extend in the direction of the length ofthe tubular core, each of the first plurality of holes establishingpaths to the bore of the tubular core; defining a second plurality ofholes oriented along a plurality of second lines that extend in thedirection of the length of the tubular core, each of the secondplurality of holes establishing paths to the core of the tubular core;and forming a plurality of channels along the first and second pluralityof lines, the plurality of channels defining recesses for distributing afluid that is configured to emanate from the bore and exit the first andsecond plurality of holes; wherein the defined first plurality of holesare offset from the defined second plurality of holes.
 17. A method ofmaking a brush core as recited in claim 16, wherein each of the firstand second plurality of holes has a diameter ranging between about 0.005inch and about 0.092 inch.
 18. A method of making a brush core asrecited in claim 17, wherein the bore has a diameter ranging betweenabout 0.060 inch and about 0.35 inch.
 19. A method of making a brushcore as recited in claim 18, further comprising: delivering a fluid flowinto the bore that is defined through the center of the tubular core,the delivered fluid flow having a pressure ranging between about 1 PSIand 15 PSI.
 20. A method of making a brush core as recited in claim 19,wherein the fluid flow pressure is about 10 PSI.